Skip encode Unicode characters in urlencode.

Our script handles these characters incorrectly, however
they can be handled by cURL with correct $LANG.

For example, when LANG=en_US.UTF-8:
`/自爆店` was encoded as `%2f%81ea%7206%5e97` (wrong). 

I modified this behavior. Now it will not encode Unicode characters any longer.
`/自爆店` will be encoded as `%2f自爆店`. 
cURL will encode this URL into `%2f%e8%87%aa%e7%88%86%e5%ba%97`

This solves issues with uploading file with Unicode characters.